Design Patterns Java™ Workbook

Relational Integrity Mediators

Part of the strength of the object-oriented paradigm is that it lets you easily map connections between Java objects and objects in the real world. However, a Java object model's ability to reflect the real world has at least two fundamental deficits. First, objects in the real world vary with time, but no support for this is built into Java. For example, assignment statements obliterate any previous value instead of remembering it, as a human would. Second, in the real world, relations are as important as objects, but relations receive little support in today's object-oriented languages, including Java. For example, there is no built-in support for the fact that if Star Press 2402 is in bay 1, bay 1 must contain ...